1. Field of the Invention
The present invention relates to an electric power supply device, an electric power supply method and an electric power supply system.
2. Description of the Related Art
For many electronic devices such as personal computers and game units, AC adapters are used that input alternating current (AC) electric power from a commercial electric power supply and output electric power that is matched to the devices, in order to operate the devices and charge their batteries. The electronic devices ordinarily operate on direct current (DC), but the voltages and currents vary according to the device. The standards for the AC adapters that output the electric power that is matched to the devices are therefore different for each device, and even AC adapters that have the same sort of shape are not interchangeable, which has created a problem in that the number of AC adapters has increased as the types of electronic devices have increased.
To address this problem, an electric power supply bus system has been proposed in which an electric power supply block that supplies electric power to devices such as a battery, an AC adapter, and the like, and an electric power consumption block to which the electric power from the electric power supply block is supplied are connected to single, common direct current bus line (refer, for example, to Japanese Patent Application Publication No. JP-A-2001-306191 and Japanese Patent Application Publication No. JP-A-2008-123051). In the electric power supply bus system, direct current electricity flows through the bus line. Furthermore, in the electric power supply bus system, each of the blocks describes itself as an object, and the objects for the respective blocks reciprocally transmit and receive information (status data) through the bus line. The object for each of the blocks also creates information (status data) based on a request from the object for the other block and transmits the created information as reply data. The object for the block that receives the reply data can then control the supply and the consumption of the electric power based on the content of the received reply data.
In the electric power supply bus system proposed in Japanese Patent Application Publication No. JP-A-2001-306191 and Japanese Patent Application Publication No. JP-A-2008-123051, a single wired electric power line is used as an electric power supply line and also as a signal line, and electric power and signals are frequency-divided while they are time-divided with respect to the electric power supply. This is because electric power with different specifications (namely, different voltages including AC and DC) is transmitted and received from pier to pier through the single bus line.